Novel boron compounds and motor fuel containing the same



United States Patent Office 3,011,880 Patented Dec. 5, 1961 3,011,880 NOVEL BORON COMPOUNDS AND MOTOR FUEL CONTAINING THE SAME Chien-Wel Liao, Beechwood, Donald D. Emrick, Shaker Heights, and Edwin 0. Hook, Chagrin Falls, Ohio, assignors to The Standard Oil Company, Cleveland, Ohio, a corporation of Ohio No Drawing. Filed May 3, 1960, Ser. No. 26,438 6 Claims. (Cl. 44-63) This invention relates to novel boron compounds and to motor fuels containing the same. More particularly, this invention relates to a class of boron compounds which serve as excellent multi-functional additives in a gasoline for a spark-ignited internal combustion engine.

The boron compounds of the present invention have the following general formula:

and wherein R represents a radical selected from a group consisting of alkyl or alicyclic radicals containing from 7 to 21 carbon atoms, and R is selected from the group consisting of hydrogen or an alkyl radical containing up to carbon atoms.

Motor fuels containing one or mixtures of the compounds of the present invention are eifective in markedly reducing many of the adverse effects resulting from combustion chamber deposits which accumulate during the prolonged operation of an initially clean engine on a hydrocarbon fuel, and particularly a hydrocarbon fuel which contains a tetra alkyl lead compound as an antiknock agent. One serious adverse effect of lead deposits is uncontrolled ignition and a general lack of smoothness in engine operation caused principally by these deposits becoming heated to incandescence within the cornbustion chamber during engine operation and igniting the fuel either before or after the portion in the cycle at which the charge would be normally ignited by the spark of the sparkplug.

Gasolines containing one or more of the boron compounds of this invention are also highly efiective in preventing carburetor deposits. Such deposits are believed to accumulate from contaminated intake air which the carburetor must breathe in in tremendous volume and are responsible for rough idling of the engine and in many cases the occurrence of frequent stalling. This condition is commonly experienced in the operation of most cars, particularly those vehicles operated in urban areas where the air is heavily contaminated with combustion products exhausted from the large population of other cars operating in the same immediate area. The condition is, of course, aggravated by any blowby fumes from the operation of the car's own engine, in addition to any industrial fumes present in the air which the carburetor breathes. These sources of contamination are additive in nature and may cause the rapid buildup of deposits on the carburetor of the engine.

Another benefit that the boron compounds of the prescut invention offer in gasoline is related to their effective ness in minimizing carburetor icing. The latter condition represents another troublesome problem attendant to automotive engines operated in cool, moist, atmospheric conditions. This icing problem is most likely to occur during engine warmup when the engine is below normal operating temperature. Vaporization of the gasoline in the carburetor during this warmup period pro duces temperature reduction of the throttle plate and carburetor walls, causing the moisture present in the incoming air on cool, humid days to condense and freeze. Such ice formation restricts the narrow openings in the carburetor, manifesting itself in a rough idling condition and frequent engine stalls.

As a still further benefit, it has been found that the compounds of the invention when used in a gasoline are valuable in assisting to safeguard against fuel line freezing in cold climatic conditions. This problem is often experienced at lower ambient temperatures when moisture which is invariably present in the fuel either from the commercial handling of the fuel or from condensation within the individual fuel tank freezes within the fuel system, thereby blocking the flow of fuel to the engine and interfering with operation. The use of lower aliphatic alcohols such as methanol, isopropariol, or mixtures thereof, in gasoline has received widespread acceptance to protect against such a freezing condition. The function of the alcohols in this respect, however, has been found to be linear with concentration; and to obtain adequate protection large amounts must be used, making the economics quite unfavorable. It has been found that the presence of compounds of the present invention in gasoline in combination with alcohol makes it possible to significantly reduce the amount of alcohol that is required to provide protection against fuel line freezing. The amount of boron compound required to obtain this effect is no more than is usually required to minimize the adverse effects of combustion chamber deposits.

In addition to offering the foregoing performance advantages in gasoline, the present boron compounds-in contrast to many organoboron compounds previously proposed for use in gasolineexhibit excellent stability in gasoline toward hydrolysis so that they may be effectively employed in large scale manufacturing and marketing operations.

The gasoline base stocks to which the present boron compounds are added may be any of those conventionally used in preparing a motor gasoline for a spark-ignited internal combustion engine, such as catalytic distillate, motor polymer, alkylate, catalytic reformate, isomerate, naphthas, etc. The gasoline will preferably contain a tetra alkyl lead compound as an anti-knock agent and a scavengingagent. The amount of the anti-knock agent will be usually at a level of approximately 3 ml./ gal. but may range from /2 ml./gal. up to 6 mL/gal. The base gasoline may also include other common additives such as anti-oxidants, stabilizers, solvent oils, dyes, and the like.

The amount of boron compounds to be added to the gasoline for purposes of the invention may vary. Generally the smallest amount that will give significant results will be in the order of 0.005% by weight. Usually amounts greater than approximately 1% by weight cannot be justified economically. The boron compounds may be added directly to the fuel or, if more convenient, they may be dissolved in a suitable solvent to produce a liquid concentrate and the concentrate blended in with the gasoline.

The boron compounds of the present invention are prepared by reacting boric acid with a N-acylated dialkanolamine compound in an equimolar relationship. The N- acylated dialkanolamine compounds employed in this reaction may be characterized by the following general formula: 7

wherein R and R are defined as hereinbefore. The latter compounds are preferably prepared by reacting a dialkanolamine compound with a fatty acid or naphthenic acid compound containing from 8 to 22 carbon atoms in a 1:1 molar ratio under conditions to remove the water of reaction. Compounds prepared by reacting diethanolamine or di-isopropanolamine with oleic acid have been found to be particularly desirable for gasoline compositions of the present invention. Commercial grades of preferred fatty acids which are derived from naturally occurring fats and oils are suitable for the preparation of these compounds, and hence the R radical in the above formula may correspond to the fatty acid radicals present in such fats and oils. The R radical may also be suitably derived from naphthenic acids containing from 8 to 22 carbon atoms.

The N-acylated dialkanolamine compounds readily undergo reaction with boric acid to form the boron com-.

pounds of the present invention under conditions in which the water of reaction may be removed from the reaction mixture as it is formed. The reaction proceeds in accordance with the equation:

in place of the boric acid as the boron source in the above reactions with the proper adjustment of the molar relationship with the N-acylated dialkanolamine compound.

The preparation of these compounds will be better understood in connection with the following examples.

EXAMPLE 1 125 grams (1.2 mols) of diethanolamine was placed in a flask with 339 grams (1.2 mols) of oleic acid, to-

gether with 300 ml. of xylene. The mixture was heated with stirring at the azeotropic distillation temperature for the complete removal of the water of reaction.

394.8 grams (1 mole) of N-oleoyl diethanolamine prepared above was placed in a flask together with m1. of xylene. To this mixture was added slowly 62 grams (1 mole) of boric acid. The mixture was heated with stirring at the reflux temperature and the water of reaction azeotropically removed. The recovery of water of reaction indicated that 2 moles of water was formed for each mole of N-oleoyl diethanolamine and boric acid reacting. The reaction mixture was then filtered to remove traces of unreacted boric acid. The product was a clear plastic material which was readily soluble in gasoline. The product has the following formula:

EXAMPLE 2 grams (1.2 mols) of di-isopropanolamine was placed in a flask with 300 ml. of xylene. To this mixture 339 grams (1.2 mols) of oleic acid was added and the mixture was then heated with stirring until the water of reaction was azeotropically distilled oif.

422.8 grams (1 mole) of N-oleoyl di-isopropanolamine prepared above was added to a flask together with 200 cc. of benzene. To this mixture was added 62 grams (1 mole) of boric acid. The mixture was refluxed together for the recovery of 2.0 moles of water. The reaction mixture was filtered and the excess solvent was removed. The product was a transparent material of a glass-like nature which was completely soluble in gasoline.

EXAMPLE 3 197.4 grams of N-oleoyl diethanolamine and 31 grams of boric acid (a 1:1 molar ratio) were mixed together in the presence of 300 ml. of toluene. The reaction mixture was heated with stirring at refluxing temperature until 2.5 moles of water was recovered for each mole of N-oleoyl diethanolamine and boric acid reacting. The product from this reaction was soluble in gasoline and had the following formula:

O-CHz-CH: (H)

N-C-CnHsa As illustrative of the benefits derived from the use of these compounds in gasoline, the following engine tests were conducted.

Engine smoothness A test procedure was devised to determine the effectiveness of test fuels in a running period to suppress vibration signals given 01f by an engine of a predetermined magnitude which may be considered other than normal engine harmonics. This test employed a 1956 Oldsmobile engine with a 11.3:1 compression ratio in which two General Radio crystal-type vibration pick-ups were attached at the front main bearing area mounted in sponge rubber. The vibrations over a predetermined magnitude were rectified and amplified and counted electronically.

To stabilize the engine with respect to combustion chamber deposits, the engine was run at 1800 r.p.m. and a manifold vacuum of 15 inches of mercury for approximately 200 hours. Then preparatory to the test cycle for each fuel, the engine was operated on the test fuel for 30 minutes at 1800 r.p.m. and 15 inches of mercury vacuum. Following this, the engine was continued at 1800 r.p.m. and the throttle opened to 8 inches of mercury vacuum for a 70-second test period in which the vibrations were counted as the result of the test. All experimental conditions were the same for each test except the gasoline.

The base fuel in each test was the same and had the following composition and specifications.

F-l Octane Rating No 99.2

In Table I below the average vibration count for seven runs made for a fuel with and without a compound of the invention is reported.

TABLE I Fuel Counts Base Fuel Base Fuel-l-Compound of Example 3 in an amount to provide 0.002% by weight boron to the fuel It will be obvious from the above data that the fuel composition of the invention is effective in promoting engine smoothness.

Carburetor cleaning To determine the effectivenessof gasoline containing these compounds to avoid carburetor deposits, a contamination system was developed to simulate the conditions which contribute to carburetor deposits in the urban operation of motor vehicles. The system comprises the operation of a slave engine and a test engine. The exhaust gas from one bank of the slave engine (four cylinders) is metered at the rate of 1.5 .cubic feet per minute to the air intake of the carburetor of the test engine. The 1.5 cubic feet per minute rate of exhaust gases from the slave engine under these conditions constitutes approximately 8% of the total air intake of the test engine at .idle manifold vacuum and speed. The operating conditions for the two engines'are as follows:

Each test cycle was 2 hours in time, which included acceleration periods on the "unloaded test engine at sixminute intervals for a period of eight seconds each. The carburetor at the start of each test was in spotless con- 'dition.- All experimental conditions werethe same for each test cycle except for the gasoline.

The base fuel in each test was the same and had the following composition and specifications.

Composition:

75% cat. distillate 25% SR naphtha A gravity 62.4

Engler distillation, F.:

6 30% 163 50% 204 70% 262 365 BR 424 Reid vapor pressure 8.75

At the end of each test cycle the carburetor was removed and disassembled and a numerical rating was assigned for amount of deposits and discoloration by a number of observers rating independently and uninformed of the gasoline they were rating. The rating assigned was based on a standardized scale ranging from to 0, wherein 100 would be a rating of a perfectly clean carburetor throttle plate and barrel, and 0 rating would represent a throttle plate and 'barrel loaded with deposits.

The results below represent the average rating by the observers:

Concentration, percent by weight None 0. 005 0. 005

None Compound of Example 1 Compound of Example 2 Carburetor anti-icing To demonstrate the carburetor anti-icing virtue of gasoline containing these compounds, a test procedure was devised simulating the stop and-go type of engine operation normally experienced by the motorist-during the engine warmup period. The test was conducted in a 1955 Plymouth V -8 engine equipped with a two-barrel carburetor. Carburetor air was supplied at a constant rate of 70 cubic feet per minute by a specially designed air conditioner controlled at 42 F. and 90% relative humidity, which are temperature and humidity conditions considered highly conducive to carburetor icing. All test conditions were the same except for the gasoline The test consisted of running the same number of cycles on each fuel where in each cycle the engine was operated at 2200 r.p.m. for 15 seconds and then decelerated normally to an idle at 450 :r.p.m. for a maximum of 30 seconds. Performance of the engine was observed during each idle period, and a numerical rating based on the degree of rough idling and engine stalls was assigned so that each fuel received a merit rating on a scale ranging from 100 to 0. By this scheme an engine operating with a smooth idle over the idle periods of every test cycle would receive a rating of 100, and an engine which stalled in less than 12 seconds in theiidle period of every test cycle would receive a rating of'O.

jThe base fuel used had the following composition and specifications.

Composition:

40% 1t. cat. distillate 40% Ultraformate 7.6% It. naphtha 8.0% isopentane Tetraethyl lead cc 3.0

Additive Rating None 0.005 Percent Compound of Example 1 F zzel line anti-freezing To demonstrate the coaction of the present boron compounds with lower aliphatic alcohols in preventing operational distress due to ice formation in the fuel system, a fuel handling system simulating that associated with an automotive engine was devised and adapted to be run in a cold box having a volume of approximately 2 cubic feet. This cold box is cooled with Dry Ice and a blower is present within the box so that the cold air may be circulated and the temperature maintained uniform. In the fuel system provided in the box a fuel tank is connected to a fuel filter by approximately 190 inches of -inch copper tubing, a fuel line length similar to the fuel line in an automobile. tion is located in the fuel line immediately after the fuel tank, similar to the type provided in the fuel system of a car as a Water trap. The fuel filter has a glass bowl so that ice formation at this point in the system may be visually detected. An electric pump is connected to the fuel filter by a short section of copper tubing. The outlet side of the pump is connected to a single-barrel carburetor by another short section of tubing in which a fiowmeter (rotameter) is located to measure the flow rate of fuel through the system. A flow valve is adapted to the carburetor to return fuel to the fuel tank. Windows are provided in the cold box at the areas where the fuel filter and the fiowmeter are located so that each of these elements may be observed by the operator during the test.

In the above equipment, fuel compositions reported in Table H below were tested at depressed temperatures to determine at what temperature operational distress would be encountered. Distress conditions for the fuel system were determined by noting when the fuel flow as indicated on the fiowmeter fell below a predetermined value, together With noting ice formation in the glass bowl of the fuel filter. The base fuel was isooctane which contained 1% by weight water.

0.25 Wt. Percent Methanol+Additive of Example 3 in an amount to provide 0.002 percent by wt. boron to the fuel From the data in Table II it will be obvious by comparing runs 3 and 4 that by the use of only small amounts of the boron compound the amount of methanol required to provide protection against fuel line freezing at low ambient temperatures is markedly reduced.

It is to be understood that various modifications of the foregoing invention will occur to those skilled in the art upon reading the above description. All such modifications are intended to be included as may be reasonably covered by the appended claims.

We claim:

1. A leaded gasoline for a spark-ignited internal combustion engine containing an amount within the range A U-tube sec- 8 of 0.005% to 1% by weight a boron com pound of the following general formula:

$1 0 CH2-CHO l R- -N B-OX CHaCHO RI t where X is selected from the group consisting of hydrogen and O-CH-CH1 o ll B No-R OC|}HCflz and wherein R represents a radical selected from the group consisting of alkyl, alkenyl, and alicyclic radicals containing from 7 to 21 carbon atoms, and R is selected from the group consistingof hydrogen and alkyl radicals containing up to 5 carbon atoms.

2. A leaded gasoline for a spark-ignited internal combustion engine containing an amount within the range of 0.005% to 1% by Weight a boron compound of the following general formula:

0 CHg-(3H2O C11 za( i3N BV-OX CHz- CHrO where X is selected from the group consisting of hydrogen and O-CH -CH; 0

o-or-n-cn,

3. A leaded gasoline for a spark-ignited internal combustion engine containing an amount within the range of 0.005% to 1% by weight a boron compound of the following general formula:

where X is selected from the group consisting of hydrogen and 4. A novel boron compound having the following general formula:

RI 0 CHz( 3HO CHr-CH-O where X is selected from the group consisting of hydrogen and wherein R represents a radical selected from the group consisting of alkyl, alkenyl, and ahcyclrc radicals containing from 7 to 21 carbon atoms, andv R is selected 9 10 from the group consisting of hydrogen and alkyl radicals where X is selected from the group consisting of hydrogen containing up to 5 carbon atoms. and

5. A novel boron compound having the following general formula: (H) /CH2CH2O\ 5 C17E33-CN /BOX O OH CH 0H,-0H, 0 /N C OH3a where X is selected from the group consisting of hydrogen and 10 CH! O-CHg-CH 0 -B N-C-C H References Cited in the file of this patent o 0H,-c, UNITED STATES PATENTS 6. A novel boron compound having the following gen- 2,741,548 Darling et a1 Apr. 10, 1956 eral formula: 15 2,939,877 Washburn June 7, 1960 2,942,021 Groszos et a1. June 21, 1960 (H) CHCH--O 2,948,597 Belden Apr. 9, 1960 C17Hs:-C-N B-OX CHz-CH-O 20 

1. A LEADING GASOLINE FOR A SPARK-IGNITED INTERNAL COMBUSTION ENGINE CONTAINING AN AMOUNT WITHIN THE RAGE OF 0.005% TO 1% BY WEIGHT A BORON COMPOUND OF THE FOLLOWING GENERAL FORMULA: 